This GFLT accelerator pump diaphragm are compatible for use with all alcohol, methanol, ethanol automotive fuel blends. They differ primarily in their resistance to fluids, and in particular aggressive lubricating oils and oxygenated fuels.
Part Reference:
Holley ...

This accelerator pump diaphragm has a GFLT style and is used to replace the existing worn-out part that is usually underneath the front of the carburetor. It is made from high-performance rubber and is designed to fit most Holley carburetors. The diaphragm has a volume of 50cc and is not recommended for use with alcohol based fuels. ...

This GFLT accelerator pump diaphragm are compatible for use with all alcohol, methanol, ethanol automotive fuel blends. They differ primarily in their resistance to fluids, and in particular aggressive lubricating oils and oxygenated fuels.
Part Reference:
Holley ...

This 50cc accelerator pump will substantially increase fuel capacity over the standard 30cc pump system. It is ideal for tunnel ram setups and for those who want increased performance for the carburetor. It eliminates flat spots off idle or at any other RPM range. This kit includes everything required for easy installation including new pump housing, stud, arm, diaphragm, spring, and longer pump ...

This accelerator pump arm is made of black plastic and is designed to fit carburetors. It includes an adjustable screw to set the air gap between the arm and the accelerator pump diaphragm housing and has a 30cc diaphragm volume. ...